W3Schools Tryit Editor

main.jsx

index.html

import React from 'react';
import ReactDOM from 'react-do/client';

const myElement = (
  <div>
    <h1>I am a Header.</h1>
    <h1>I am a Header too.</h1>
  </div>
);

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(myElement);

<!doctype html>
<html lang="en">
  <body>
    <div id="root"></div>
    <script type="module" src="/src/main.jsx"></script>
  </body>
</html>